Native UI goes far beyond the look. Another concern is accessibility, especially for blind users. Non-native UIs can be accessible, but only if the toolkit impl

Native UI goes far beyond the look. Another concern is accessibility, especially for blind users. Non-native UIs can be accessible, but only if the toolkit implements each platform's accessibility API, and gets the implementation right, which seems to be very difficult. (For example, last time I checked, Qt's implementation of the relevant accessibility APIs on Windows was deficient enough that the TeamTalk voice chat client offers a "classic" MFC-based client specifically for blind users.)